It is in going to Mars that we will learn how to successfully survive in space and also on another planetary body. This is the best insurance against the total extinction of humanity by some planetary catastrophe.
It is imperitive that we learn how to do this as quickly as possible.
The proof isn’t in the pudding, the raisins are in the pudding. The proof of the pudding is in the eating.
Spacecraft propulsion
Will Nuclear Power Put Humans On Mars?
The Bush admin. has been talking about restarting nuclear engine research practically since day one. It’d make a great secret project, but even if they fund it, I don’t see how they can slip it past the anti-nuke fringe.